Test devices for the detection of occult blood are constituted of a carrier in which organic hydroperoxide, coloration indicator, buffering agent, wetting agent, activating agent and stabilizer are impregnated. If hemoglobin is present in a specimen, the organic hydroperoxide is activated to produce nascent oxygen with which the indicator is oxidized and develops color. As the organic hydroperoxide are known 2,5-dimethylhexane-2,5-dihydroperoxide and cumene hydroperoxide. Whereas these peroxides are in practical use, they are disadvantageous in remarkably reducing of the detective sensitivity due to lack of stability with elapse of time, pseudonegative judgement when vitamin C is contained in the urine specimen, reduction of capacity in the multi-item test pieces for the detection of urinary components caused by discoloration of the adjacent test pieces, low coloration sensitivity, etc. Compounds in which the benzene ring of cumene hydroperoxide is provided with a substituent such as a C.sub.1-6 alkyl group, Cl, Br, I, NO.sub.2 or carboxyl group have recently been proposed as the hydroperoxide with which these disadvantages are improved (Japanese Patent LOP Publication No. 190663/1984). Although the peroxides represent considerable improvement over the known compounds, the stability with elapse of time is not yet satisfactory.